Friction Versus Frictionless Mechanics During Maxillary En-masse Retraction in Adult Patients

Friction Versus Frictionless Mechanics During Maxillary En-masse Retraction in Adult Patients With Class I Bimaxillary Dentoalveolar Protrusion: A Randomized Clinical Trial

This study is a Randomized clinical trial comparing the effectiveness of two different mechanics during maxillary en-masse retraction in adult patients. Patients will be randomly divided into two groups:Friction and frictionless mechanics. Mini screws will be used in both group to ensure maximum anchorage during retraction. Lateral cephalometric radiographs and dental models will be taken for each patients pre and post -retraction. Following complete anterior segment retraction, the rate and duration of retraction will be evaluated for both groups as well as patient satisfaction with treatment. Changes in incisors inclination and soft tissue as well as anchorage loss will be also assessed.

Adult patients with Class I bimaxillary dentoalveolar protrusion will be recruited. All the patients need extraction of upper first premolars followed by anterior segment retraction and maximum anchorage.

The patients will be randomly allocated to one of two groups; either Friction or Frictionless group. In friction group, Nickel Titanium coil spring will be used for retraction of anterior segment while in frictionless group, T-loops will be used for retraction. All the patients will receive two miniscrews , one on each side to achieve maximum anchorage during retraction.

The patients will be seen on a monthly basis for follow up visit for activation of the appliance to maintain constant force during the study. An impression will be taken for the patients every visit, poured into stone for fabrication of dental models. The models will be used to monitor the rate of retraction of anterior teeth.

Every patient will be asked for lateral cephalometric radiograph before and after complete retraction. After data collection, two assessors will carry on the measurements blindly and independently. Statistical analysis of the data will be done and the results will be compared to evaluate the effectiveness of both techniques for en-masse retraction.

Inclusion Criteria:

1. Male or female adult patients with age range 18-30 yrs old.
2. Class I bimaxillary dentoalveolar protrusion .
3. Full permanent dentition.
4. Good oral hygiene.
5. Maximum anchorage is required.
6. Healthy bone between first molars and second premolars is needed.

Exclusion Criteria:

1. Systemic disease.
2. Severe crowding.
3. Extracted or missing upper permanent tooth/teeth (except for third molars).
4. Any signs or symptoms or previous history of temporomandibular disorders (TMD).
5. Previous orthodontic treatment.